Seat belt apparatus for automobile

Abstract

A seat belt apparatus for an automobile includes a ratchet wheel and at least one pawl member for selectively braking a spool with respect to one direction of its rotation. The pawl member operates to perform the emergency locking and excessive-loosening preventing functions with respective to a belt. To precisely control the time for emergency stop of belt, the apparatus contains a fly wheel mass having a plurality of holes, and a web sensing spring one end of which is fixed to one of the holes. Further, to control the effective length of the belt, the apparatus includes cam protrusions, a cam gear and a cam plate which overlap to enable the distance control of the cam protrusions.

What is claimed is: 
     
       1. A seat belt apparatus for an automobile, comprising: a belt;   a spool for rotating in a first direction to wind said belt around said spool; and for rotating in a second direction opposite to said first direction to unwind said belt from said spool;   a rewinding spring for rotating said spool in said first direction to wind said belt around said spool when said belt is forcibly pulled to rotate said spool in said second direction;   a ratchet wheel integrally connected with said spool and rotating with said spool;   at least one pawl member for selectively engaging said ratchet wheel to prevent rotation of said ratchet wheel and said spool in said second direction; and   emergency stopping means for enabling said at least one pawl member to engage said ratchet wheel and prevent rotation of said ratchet wheel and said spool in said second direction, said emergency stopping means comprising:   a locking ring having a saw-toothed portion formed on an inner periphery of said locking ring and a first cam slot formed on an outer portion of said locking ring, said locking ring being biased to rotate in said first direction; flywheel means having a second cam dot and in said flywheel means said flywheel means being biased to rotate in said second direction;   hooking means having a pin positioned within said second cam slot of said flywheel means, said pin traversing said second cam slot and enabling said hooking means to engage said saw-toothed portion of said locking ring and cause rotation of said locking ring in said second direction when a first force rotating said spool in said second direction exceeds a second force biasing said flywheel means to rotate in said second direction, said at least one pawl member engaging said ratchet wheel and preventing rotation of said ratchet wheel and said spool in said second direction in response to rotation of said locking ring in said second direction.     
     
     
       2. The seat belt apparatus as claimed in claim 1, further comprised of means for applying said second force to bias said flywheel means to rotate in said second direction being manually adjustable by user to vary a magnitude of said second force. 
     
     
       3. The seat belt apparatus as claimed in claim 1, wherein said first plurality of holes formed in said flywheel means accommodate insertion of one end of a sensing spring that biases said flywheel means to rotate in said second direction, said second force being adjusted by a user by inserting said one end of said sensing spring into a selected one of said first plurality of holes. 
     
     
       4. The seat belt apparatus as claimed in claim 1, further comprising means for preventing loosening of said belt beyond a predetermined limit by preventing rotation of said ratchet wheel and said spool in said second direction whenever said belt is unwound from said spool by an amount corresponding to said predetermined limit. 
     
     
       5. The scat belt apparatus as claimed in claim 4, wherein said means for preventing loosening of said belt comprises: locking means for engaging said ratchet wheel to prevent the rotation of said ratchet wheel and said spool in said second direction;   at least one gear member for rotating in response to rotation of said ratchet wheel and said spool;   a cam gear having a first protrusion and rotating in response to rotation of said at least one gear member;   a cam plate integrally connected to said cam gear to rotate concentrically with said cam gear, said cam plate having a second protrusion positioned a predetermined distance from said first protrusion; and   a cam lever comprising first and second interlocking portions for respectively engaging said first and second protrusions to enable rotation of said cam lever in dependence upon rotation of said cam gear and said cam plate, said cam lever further comprising a third interlocking portion for enabling said locking means to engage said ratchet wheel in dependence upon rotation of said cam lever.   
     
     
       6. The seat belt apparatus as claimed in claim 5, further comprising a second plurality of holes formed within and positioned circumferencially around said cam gear and a pin extending outwardly from said cam plate, said pin inserting into one of said second plurality of holes to control said predetermined distance between said first protrusion and said second protrusion. 
     
     
       7. The seat belt apparatus as claimed in claim 6, wherein said predetermined distance between said first protrusion and said second protrusion determines said predetermined limit that said belt can be loosened. 
     
     
       8. The seat belt apparatus as claimed in claim 7, wherein said predetermined limit that said belt can be loosened is adjustable by a user. 
     
     
       9. A seat belt apparatus for an automobile, comprising: a belt;   a spool for rotating in a first direction to wind said belt around said spool, and for rotating in a second direction opposite said first direction to unwind said belt from said spool;   a ratchet wheel having a first saw-toothed portion formed on an outer periphery and rotating concentrically with said spool, said spool rotating in said first direction whenever said ratchet wheel rotates in said first direction and said spool rotating in said second direction s whenever said ratchet wheel rotates in said second direction;   a locking ring having a second saw-toothed portion formed on an inner periphery of said locking ring and a first cam slot formed on an outer portion of said locking ring, said locking ring being biased to rotate in said first direction;   pawl means having a first pin positioned within said first cam slot of said locking ring, said first pin traversing said first cam slot and causing said pawl means to engage said first saw-toothed portion and prevent rotation of said ratchet wheel and said spool in said second direction in response to rotation of said locking ring in said second direction;   flywheel means having a second cam slot and a first plurality of holes formed in said flywheel means, said flywheel means being biased by a spring to rotate in said second direction; and   hooking means having a second pin positioned within said second cam slot of said flywheel means, said second pin traversing said second cam slot and enabling said hooking means to engage said second saw-toothed portion and cause rotation of said locking ring in said second direction when a first force rotating said spool in said second direction exceeds a second force biasing said flywheel means to rotate in said second direction.   
     
     
       10. The apparatus as claimed in claim 9, further comprised of said second force biasing said flywheel means to rotate in said second direction being adjustable by a user. 
     
     
       11. The apparatus as claimed in claim 10, wherein said second force exhibits a magnitude in dependence upon placement by the user of a protruding end of said spring into one of said first plurality of holes formed in said flywheel means. 
     
     
       12. The apparatus as claimed in claim 11, further comprising a rewinding spring for causing rotation of said spool in said first direction to wind said belt around said spool when said belt is forcibly pulled to rotate said spool in said second direction. 
     
     
       13. The apparatus as claimed in claim 9, wherein said second force exhibits magnitude in dependence upon placement by a user of a protruding end of said spring into one of said first plurality of holes formed in said flywheel means. 
     
     
       14. The apparatus as claimed in claim 9, further comprising a rewinding spring for causing rotation of said spool in said first direction to wind said belt around said spool when said belt is forcibly pulled to rotate said spool in said second direction. 
     
     
       15. The apparatus as claimed in claim 9, further comprising means for preventing loosening of said belt beyond a predetermined limit by preventing rotation of said spool in said second direction whenever said belt is unwound from said spool by an amount corresponding to said predetermined limit. 
     
     
       16. The apparatus as claimed in claim 15, wherein said means for preventing loosening of said belt comprises: locking means for engaging said ratchet wheel to prevent the rotation of said ratchet wheel and said spool in said second direction;   a cam gear having a first protrusion and rotating in response to rotation of said spool;   a cam plate concentrically connected to said cam gear to rotate with said cam gear, said cam plate having a second protrusion positioned a predetermined distance from said first protrusion; and   a cam lever comprising first and second interlocking portions for respectively engaging said first and second protrusions to enable rotation of said cam lever in dependence upon rotation of said cam gear and said cam plate, said cam lever further comprising a third interlocking portion for enabling said locking means to engage said ratchet wheel in dependence upon rotation of said cam lever.   
     
     
       17. The seat belt apparatus as claimed in claim 16, further comprising a second plurality of holes formed within and positioned circumferencially around said cam gear and a pin extending outwardly from said cam plate, said pin inserting into one of said second plurality of holes to control said predetermined distance between said first protrusion and said second protrusion. 
     
     
       18. The apparatus as claimed in claim 17, wherein said predetermined distance between said first protrusion and said second protrusion determines said predetermined limit that said belt can be loosened. 
     
     
       19. The seat belt apparatus as claimed in claim 18, wherein said predetermined limit that said belt can be loosened is adjustable by a user. 
     
     
       20. A seat belt apparatus for an automobile, comprising: a belt;   a spool for rotating in a first direction to wind said belt around said spool and for rotating in a second direction opposite said first direction to unwind said belt from said spool;   a rewinding spring for rotating said spool in said first direction to wind said belt around said spool when said belt is forcibly pulled to rotate said spool in said second direction;   a ratchet wheel integrally connected with said spool and rotating concentrically with said spool; and   means for preventing loosening of said belt beyond a predetermined limit by preventing rotation of said ratchet wheel and said spool in said second direction whenever said belt is unwound from said spool by an amount corresponding to said predetermined limit, said means for preventing loosening of said belt comprising: locking means for engaging said ratchet wheel to prevent the rotation of said ratchet wheel and said spool in said second direction;   a cam gear having a first protrusion and a plurality of holes formed within and circumferencially around said cam gear, said cam gear rotating in response to rotation of said ratchet wheel and said spool;   a cam plate integrally connected to said cam gear to rotate concentrically with said cam gear, said cam plate having a second protrusion positioned a predetermined distance from said first protrusion and a pin that inserts into one of said plurality of holes formed in said cam gear to control said predetermined distance between said first protrusion and said second protrusion, said predetermined distance between said first protrusion and said second protrusion being indicative of said predetermined limit that said belt can be loosened; and   a cam lever comprising first and second interlocking portions for respectively engaging said first and second protrusions to enable rotation of said cam lever in dependence upon rotation of said cam gear and said cam plate, said cam lever further comprising a third interlocking portion for enabling said locking means to engage said ratchet wheel in dependence upon rotation of said cam lever.     
     
     
       21. The seat belt apparatus as claimed in claim 20, wherein said predetermined limit that said belt can be loosened is adjustable by a user. 
     
     
       22. A scat belt apparatus for an automobile, comprising: a belt;   a spool for rotating in a first direction to wind said belt around said spool, and for rotating in a second direction opposite said first direction to unwind said belt from said spool;   a rewinding spring for rotating said spool in said first direction to wind said belt around said spool when said belt is forcibly pulled to rotate said spool in said second direction;   a ratchet wheel integrally connected with said spool and rotating concentrically with said spool;   emergency stopping means for preventing rotation of said ratchet wheel and said spool in said second direction in response to occurrence of a force urging said belt to unwind from said spool with a magnitude beyond a first predetermined limit capable of being set by a user; and   means for preventing loosening of said belt beyond a second predetermined limit by preventing rotation of said ratchet wheel and said spool in said second direction whenever said belt is unwound from said spool by an amount corresponding to said second predetermined limit, said means for preventing loosening of said belt comprising: locking means for engaging said ratchet wheel to prevent the rotation of said ratchet wheel and said spool in said second direction;   a cam gear having a first protrusion and a plurality of holes formed within and circumferencially around said cam gear, said cam gear rotating in response to rotation of said ratchet wheel and said spool;   a cam plate integrally connected to said cam gear to rotate concentrically with said cam gear, said cam plate having a second protrusion positioned a predetermined distance from said first protrusion and a pin that inserts into one of said plurality of holes formed in said cam gear to control said predetermined distance between said first protrusion and said second protrusion, said predetermined distance between said first protrusion and said second protrusion being indicative of said second predetermined limit that said belt can be loosened; and   a cam lever comprising first and second interlocking portions for respectively engaging said first and second protrusions to enable rotation of said cam lever in dependence upon rotation of said cam gear and said cam plate, said cam lever further comprising a third interlocking portion for enabling said locking means to engage said ratchet wheel in dependence upon rotation of said cam lever.     
     
     
       23. The seat belt apparatus as claimed in claim 22, wherein said second predetermined limit that said belt can be loosened is adjustable by the user.